The present invention relates to a branch trimmer and, more particularly, pertains to a new and improved branch trimmer for cutting branches of a tree, and the like, by reciprocating a saw blade thereof in a longitudinal direction.
In a conventional branch trimmer of this kind used for the cutting or trimming of branches, which may be located at an elevated position, such as for example, high branches on roadside or garden trees, an output of rotational power from a power source, such as a small two-cycle gasoline engine, mounted on an operation sleeve at the base end thereof, is transmitted to a reciprocating saw blade attached to the other end of the operation sleeve, which, in turn, is capable of cutting the branches by abutting the saw blade against them.
The assignee of the present invention have proposed a branch trimmer, as disclosed in Japanese Examined Utility Model Publication No. Hei 4-23395, wherein a momentum converter converting rotary motion of the output of the power source into linear reciprocation is mounted on the operation sleeve at the end thereof on the side of the saw blade, in which the power source and the momentum converter are connected by a rotation shaft disposed within a telescopic operation sleeve.
Such a branch trimmer comprises four guide rollers having grooves for slidably reciprocating the saw blade while regulating the both sides thereof, wherein the saw blade and whole the bottom portion of the gear case are covered with an integrally formed gear case cover. In the former prior art, as described above, when a replacement of the saw blade is required, the gear case must be removed in order to open the entire momentum converter, then the tip of a driver tool is inserted between the saw blade and a small end of a connecting rod and the driver tool is forcibly pulled down so that a pin on the small end of the connecting rod can be removed from the pin fitting bore. However, this kind of prior art apparatus has problems in that replacement of the saw blade requires very troublesome work. Moreover, the gear case is susceptible to receipt of foreign substances, such as dust, because the entire bottom portion of the gear case must be opened when replacing the saw blade. Thus, in such apparatus, the durability of the momentum converter device, and the like, is jeopardized and the need to disassemble the apparatus may cause loss of parts.